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Status Flags HMI (Human-Machine Interface) Classes |
Status FlagsEvery object derived from PegThing has a status which can be set queried with StatusIs and manipulated with AddStatus and RemoveStatus. An application generally should never attempt to modify these flags, however it is sometimes useful to read this value to test for certain object states. The following status flags are available: PSF_VISIBLEThe object is visible on the screen. This flag should not be modified by the application level software. Clearing or setting this flag will not have the effect of removing or displaying the object. The PegThing member functions Add and Remove are used for that purpose. PSF_CURRENTthe object is in the current branch of the display tree. If is current, then it is the object which will receive keyboard input messages. PSF_SELECTABLEThis flag is tested by PegPresentationManager to determine messages. The application level software can modify this flag. PSF_SIZEABLEdetermines whether or not an object can be resized. The application can modify this flag. PSF_MOVEABLEdetermines whether or not an object can be moved. The application can modify this flag. PSF_NONCLIENTallows a child object to draw outside the client area of its parent. The application can modify this flag after the object is constructed but before the object is displayed. PSF_ACCEPTS_FOCUSindicates that the object will become the receiver of input events when selected. The application can modify this flag, but normally this is not advised. If this flag is modified for a particular object, it is important for correct operation that 'breaks' in the tree of objects accepting focus are avoided. In other words, if a parent window cannot accept focus, then neither should any of the window's child objects be allowed to accept focus. PSF_ALWAYS_ON_TOPThis flag insures that the object is always on top of its siblings. The application level software can modify this flag. PSF_VIEWPORTinstructs PegPresentationManager that the object should be given a private screen viewport. Objects that have a viewport are drawn differently than objects that do not have a viewport. In general, large objects or objects which have a very complex drawing routine should be given viewports, while small or simple objects should not. By default all PegWindow derived objects receive viewports, and all other objects do not. This flag should not be changed except immediately after the object is constructed.
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